DE 42 30 183 C2 discloses a control device for hydraulic motors comprising at least one directional control valve, which may be connected via a supply line to a pump acting as pressure supply device, via a discharge line to a tank or return connection and via at least one output line to a hydraulic motor. A supply line regulator is disposed in the supply line. A control line is applied with a load-dependent control pressure that may be connected to the output line via a load sensor disposed in the directional control valve. The load sensor may be activated directionally-dependent, and with at least one relief line that leads from the control line via the directional control valve to the discharge line. At least one safety valve is disposed in the relief line. The safety valve may be activated into an open position when a predetermined load limit or movement limit is reached. The relief line in the directional control valve may be switched into the open position depending on direction and synchronously with the respective activated load sensor.
Because the safety valve in the known solution is disposed in a section of the relief line that is located between the port of the directional control valve and the discharge line, the section of the relief line that contains the safety valve remains depressurised until the safety valve is used for the monitoring of the movement direction of the hydraulic motor that is assigned to it. Thus, the known solution ensures that different safety valves may be defined for each movement direction independently.